In Patent Document 1, there is disclosed a heater built-in valve including a valve box provided with a fluid passage, a casing provided above the valve box, a valve rod that moves up and down a valve element opening and closing the fluid passage, a piston arranged movably upward and downward inside the casing and fixed to the valve rod, piston driving means for moving up and down the piston, and a heater that heats a vicinity of the valve element. The heater is intended to prevent gas flowing through the valve from being solidified, and heats the gas to 130° C. to 150° C.
Patent Document 1: Unexamined Japanese Patent Publication No. H7-198063